Backend: Refine sel ir optimization
Backend: Refine sel ir optimization

We may have some inst like:
        mov %30, %3
(-f0.1) mov %30, %4
(+f0.1) mov %30, %5
to mask some value out with the flag.
Now only the last mov will left after optimization.
This patch add check about if the intemedia can be replaced even if they
are in the same prediction state and inverse prediction state.
Also refine the check of prediction state to propoly handle situation:
(-f0.1) infoinst %30, %4
        inst     %30, %8

Signed-off-by: Pan Xiuli <e5a665b1e626c5dc0826076a8b5a209eb48bf6ee@intel.com>
Reviewed-by: Guo Yejun <1f883e24fa2949df61a83c432caa290810cece11@intel.com>

wdv4758h/beignet,wdv4758h/beignet,wdv4758h/beignet,wdv4758h/beignet,wdv4758h/beignet